The present application relates generally to ultrasonic imaging systems. In particular, the present application relates to methods and systems for suppressing structure in real-time across sequential scanned volumes.
Conventional ultrasonic systems are capable of acquiring data representative of a scanned volume, and processing and displaying the acquired data as an image. The acquired data may have three-dimensional (“3D”) information corresponding to the scanned volume. Similarly, the image may appear 3D based on information in the acquired data. Over a period of time, an ultrasonic system may acquire a sequence of 3D datasets, which may be processed and displayed as a sequence of 3D images. Alternate names for a sequence of acquired 3D datasets or images include dynamic 3D data and four-dimensional (“4D”) data. Conventional ultrasonic systems may also include a feature to suppress a portion of acquired data or images. For example, the Voluson 730 by General Electric allows a user to suppress a portion of a 3D scanned volume using the “MagiCut” feature. This feature is detailed extensively in the V730 Expert BT04 Basic User Manual, G.E Part Number KTI 105 927-100. MagiCut allows a user to suppress a volume by selecting an area from an ultrasonic image.
As described in V730 Expert BT04 Basic User Manual, six suppression methods are available with MagiCut. These different methods can be used in different cases depending on the user's goals. The first suppression method is “Inside Contour”: With this suppression method the part of the image within the contour (drawn freehand) is suppressed. If a contour is left open, the program automatically closes the contour with a straight line from the ending point to the starting point. The second suppression method is “Outside Contour”: All parts of the image that lie outside of the contour (drawn freehand) are suppressed. If a contour is left open, the program automatically closes the contour with a straight line from the ending point to the starting point. The third suppression method is “Inside Box”: While holding down the right mouse button, move the mouse in a diagonal fashion from the beginning cut point to the end cut point in order to create a box. The part of the image inside the box is suppressed. The fourth suppression method is “Outside Box”: Using the same way of drawing as with “Inside Box,” draw a box. All parts of the image that lie outside the box are suppressed. The fifth and sixth suppression methods are “Small Eraser” and “Big Eraser”: Hold down the right mouse button and move across the image. Any area touched by the mouse cursor will be suppressed. MagiCut also allows the user to define a cut depth, so that the entire volume depth may be suppressed, or only a portion of the volume depth may be suppressed. In addition to the methods of cutting available with MagiCut, various other image editing techniques are widely known to accomplish volume suppression.
FIG. 2 illustrates an example of 3D volume suppression. An unsuppressed 3D image 10 and a 3D image with volume suppression 12 are shown side-by-side. The unsuppressed image 10 shows legs of a fetus and additional tissue and matter. The image with volume suppression 12 includes the legs 14, and a suppressed volume 16. Note that a 3D image contains information corresponding to three dimensions, and thus appears three-dimensional, although it may be displayed on a substantially two-dimensional display.
FIG. 3 illustrates another example of 3D volume suppression. FIG. 3 shows two images 18, 20 side-by-side. For reference, a depth axis 19 is shown in each image 18, 20. On the left is an ultrasonic image with full-depth suppression 18. In this type of volume suppression, a selected area is suppressed through the full depth of the image. On the right is an ultrasonic image with partial-depth suppression 20. In partial-depth volume suppression, a selected area is suppressed to a depth that is less than the full depth of the image.
FIG. 1 illustrates a schematic block diagram of a conventional ultrasonic imaging system with 3D imaging and structure suppression. An ultrasonic imaging system 100 includes a transmitter 134 that drives a transducer 132. The transducer 132 emits ultrasonic signals into a volume of interest 130. Some of the emitted signals are backscattered from the volume of interest 130 to the transducer 132. A receiver 136 receives the backscattered signal. The backscattered signal may be representative of a portion of the volume of interest 130. The receiver 136 communicates with a memory 138 to store ultrasonically gathered data representative of the volume of interest 130. The ultrasonically gathered data may contain information corresponding to a variety of coordinate systems. For example, the data may contain information corresponding to a topical coordinate system. The transmitter 134, transducer 132, and receiver 136 may influence the coordinate mapping that corresponds to the ultrasonically gathered data.
It may be practical to convert the ultrasonically gathered data into a three-dimensional Cartesian coordinate system. To accomplish this conversion, the ultrasonically gathered data may be processed by a volume scan converter 140. The 3D dataset may be stored in memory 142. A suppression structure generator 146 retrieves the 3D dataset from memory 142. A user 144 interacts with a suppression structure generator 146. Using image editing techniques, the user 144 may select a structure for suppression with the suppression structure generator 146. The suppression structure generator 146 may store a 3D dataset with structure suppression in memory 142. The volume rendering processor 148 may then retrieve the dataset and transform the dataset into a viewable image. A video processor 150 and display 152 may display a viewable image to the user.
While conventional ultrasonic imaging systems conveniently facilitate volume suppression in a single 3D scanned image, it is much more difficult and time consuming to accomplish volume suppression in multiple 3D images or 4D images with such systems. One way to accomplish 4D suppression (i.e. suppression in a sequence of 3D volumes) is for a user to select a volume for suppression on a 3D scanned image, and to open a subsequent 3D image and repeat the process of selecting a volume for suppression. Such a procedure is memory intensive, time consuming, and inconvenient. Additionally, manual intervention on a frame-by-frame basis removes the possibility of providing real-time suppression of structure in 4D ultrasonic images.
Thus there is a need for methods and systems to suppress structure in 4D ultrasonic data without repeated user intervention. There is a need for methods and systems to suppress structure in 4D ultrasonic data in real-time. There is also a need to implement such systems and methods efficiently and inexpensively.